So at the end of the Prisoner of Azkaban, Sirius says to Hermione, "You really are the brightest witch of your age," with an emphasis on the "are", implying that someone previously had told him that Hermione was super fucking smart and he was just then affirming it.
But like, who told him that? He didn't really get a chance to talk to Harry or Rob or Lupin between "I didn't kill your parents" and "oh shit werewolf" and "I'm about to get the Dementors Kiss"
So I like to think that it was Crookshanks who told him, cuz Crookshanks And Padfoot we're friends right? I can just imagine Crookshanks going on and on about Hermione, like "My human is the best human, she's so smart and lovely and perfect, just wait till you meet her, I love her so much."
